Slack eliminator for shoe patching machines



Dec. e, 1938. N ETERS 2,138,981

SLACK ELIMINATOR FOR SHOE PATCHING MACHINES Filed Oct. 14, 1937 mwawa/f? Ava/04 925 PETA-7 53am. 6V 9/V/Vfi-AUP54 P572795, 6.0).

H IS ATTORNEY.

Patented Dec. 6, 1938 PAT OFFICE SLACK ELIMINATOR FOR "SHOE PATCHING MACHINES Nicholas Peters, deceased, late or Cleveland, Ohio,

by Anna, Lupsa Peters, administratrix, Cleveland, Ohio Application October 14, 1937, Serial No. 168,924 81 Claims. (or. 112-221) This invention relates to a slack eliminator for sewing machines and particularly to a device for use in connection with sewing machines of the upper and patching type of shoe repair machines.

One of the objects of the present invention is to eliminate the slack of the various operating and reciprocating elements of the machine so that vibration and impact stresses are reduced and smooth operation is effected.

Another object is so to tension various parts of the machine that the needle will reciprocate in an accurate axial path at all times.

A correlative object of the invention is to retain various working parts of the machine in proper alignment and relative positions by a yielding pressure so that smooth and accurate operation is assured.

A more specific object is to maintain the elements so stressed that the needle can be driven through much heavier materials than it could were the device not used, even in the case of new and unworn machines of this type.

Another object of the present invention is to provide a simple and economical device which may be readily attached to the commonly used types of shoe upper sewing and patching machines for effecting the results above set forth.

Other objects and advantages will become apparent from the following specification wherein reference is made to the drawing.

In the drawing:

Fig. 1 is a somewhat diagrammatic plan view of a well known type of shoe patching machine, showing a device incorporating the principles of the present invention installed thereon in operating position;

Fig. 2 is an enlarged perspective view of a part of the device and one of the elements of the sewing machine illustrated in Fig. 1 showing the cooperation therebetween.

Fig. 3 is an enlarged sectional view taken on a plane indicated by the line 33 of Fig. 1.

For the purpose of illustration there is shown a preferred embodiment of the device mounted for cooperation with a Singer sewing machine of the shoe upper sewing and patching type, which machine is so Well known in the trade and so nearly the exclusively used machine that its parts and operation are well known to substantially every shoe repair man.

The sewing machine consists generally of a horizontally extending base I, having at its outermost end the usual bobbin adapted for cooperation with the needle, and a substantially horizontal arm 2, spaced above the base and containing various mechanical elements of the machine. At the outer end of the arm 2 is the usual enlarged portion in which is carried the usual upright needle bar guide. A needle bar 3 is mounted for reciprocation vertically in the needle bar guide and carries the usual needle. Mounted in and extending longitudinally of the arm 2 is the main driving shaft at the inner end of which is a main driving pulley 4 which is driven by a belt 5. from a suitable source of power. Mounted on the same end of the shaft and rotatable therewith is a cam disc 6 having oppositely facing cam surfaces 1 and 8, each of which in. turn, is adapted, during driving, to cooperate with and drive a driving lever 9 along different respective portions of the path of rotation of the cams.

On the arm 2, extending longitudinally thereof, is theusual needle driving bar lever 10, this lever being mounted on a suitable transverse pivot ll positioned about midway between the ends of the arm 2, so that the lever Ill may rock in a vertical plane. a rigid frame on one end of which is secured the driving lever 9 which engages with the cams 1 The lever preferably consists of and 8 during respective parts of the revolutions of the disc 6, so as to rock the lever ID in a vertical plane consequent upon rotation of the disc 6. At theopposite end, the lever'lfl is provided with a guide, which maybe in the form of a suitable sleeve l2, the guide extending longitudinally of the lever l0. Mounted for reciprocable axial movment in the sleeve or guide I2 is a piston IS, the outer end of which is connected to the upper end of the needle bar 3 by means of a transversely extending pivot M. The piston l3 isnotched at its innermost end, as indicated at IS in Fig. 2, for a purpose later to be described. 0n the same end of the lever ID and rockable in the same plane as this lever is a thread take-up lever l-B, mounted ona suitable transverse pivot ll. The purpose of the thread take-up lever I6 is well understood to be for feeding the thread properly.

The take-up lever l6 preferably extends through a suitable slot in the lever l0 so that the innermost end portion l8 protrudes into the sleeve 12 and into the slot l5 of the piston l3, forming an operating cam. The usual spring I9 is provided for normally holding and returning the take-up lever I6 to the uppermost position.

In the usual operation of the machine, since the outer end of the lever l0 adjacent the needle bar swings through a. slightarc and since the pivot I4 and end of the piston l3 connected thereto must move along. a vertical line at its pivot joint, the axial movement of the piston l3 compensates for the correlation between the arcuate path of the lever l0 and the straight path of the pivot l4, allowing the outer end of the piston to travel axially of the needle bar 3.

The end wall 2| of the slot IS in the piston is so arranged as to abut the end portion or cam I8 of the lever [6 so as to rock the thread takeup lever 16 as the piston reciprocates in the sleeve. Thus axial movement of the piston effects an additional operation.

When the sewing machine has been operated for a considerable period, or even on a new machine when used for very heavy work it is. found that there is considerable play between the complementary bearing surfaces of'the pivot H and its supports on the arm 2, or between the complementary bearing surfaceof-the lever l0 and pivot I l, as the case may be. Likewise, there is considerable play between the bearing surfaces of the needle bar 3 and ofthe piston [3 respectively and the complementary bearing surfaces of the pivot I 4. Objectionable wear also occurs in the sleeve l2 so that the-piston I3 is not properly retained in place or in true axial position but may rock slightly in a vertical plane and laterally also in the sleeve. In addition there is wear in the surface of the cam IB of the thread take-up lever and the end wall 2| of the piston slot. In addition to this wear, the driving lever 9 and the cooperating surfaces of the cams 1 and 8 become worn so that the lever 9 tends to vibrate and slap back and forth between the two driving cams, especially when and for an interval after shifting from one to the other. Again the needle'bar 3 tends to rock toward and away from the lever l0 and invariably takes such a position that it disposes the needle on a slight slant inwardly of the machine, as indicated diagrammatically by the dot-dash line- 22, the slope of which is exaggerated for clearness in illustration. The slack and inaccurate fitting in these various parts cause pounding and vibration in the machine which necessarily is transmitted throughout all the internal mechanism and tends toward further wear and looseness and inefiicient operation of the internal moving elements.

As stated the present inventionmay be readily installed on such a machine andwill overcome all of these objections and insure efficient operation. The preferred form' of the device which has been shown by way of illustration consists of a tension spring 30, which is anchored at one end, for example, by securing the same to the arm 2 of the machine by means of a suitable retaining band 3| adapted to surround and firmly engage the arm 2. The opposite end of the spring 30 is secured to the lever 10 preferably about midway between its pivot H and the outermost end. Since in 'most of the machines, the lever I0 is made in the general form of beam of the lace bar web type of constructions, this end of the spring may easily be attached to a collar 33, preferably of resilient metal, which isopen along the outermost face so as to be snapped onto the lace member 34 of the lever ill. The lower part of the collar wall engages the outer frame-member of the lever ID, as indicated at 35, one end projecting therebeyond and being provided with a hook over which the upper end of the spring 30 s secured. At the upper end the collar 33 is provided with a hook 36 which is adapted to receive the inner end of a tension spring 31. The outer end of the sp'ring'is secured to the inner end of a yoke, the arms 38 ofwhich extend outwardly around the end of the lever H3 and the sleeve I2 so as to be spaced slightly therefrom. The outer ends of the arms 38, as better illustrated in Fig. 2, pivotally engage the pivot It. The hook 36 is preferably so positioned that when the spring 37 is installed and tensioned, the pull of the spring is substantially axially of the piston [3 or slightly upwardly from the axis of the piston.

Mounted between the yoke arms 33 at their outer end is a stirrup spring 40, the upper ends of which hook over the upper outer edges of the yoke arms, as better illustrated in Fig. 2. The stirrup 40 hangs downwardly from the yoke arms so as to pass beneath the piston i3, thus forming a supporting rest therefor. This portion of the stirrup is bent upwardly slightly at the center to form a peak or rest 42 adapted to engage a small notch 42a in the underside of the piston l3 and fit snugly in the same, thus holding the piston in the middle of the stirrup and in fixed circumferential position in its sleeve. The rest portion of the cradle is yieldably movable vertically. The arms 33 of the stirrup are preferably so spaced laterally that they snugly embrace the side portions of the piston l3, as better illustrated in Fig. 3.

Referring to the operation of various elements of the device and the manner in which they 00- operate to produce a unified and efficient result, the stirrup spring is hooked on the yoke arms 38 in the position shown in Fig. 2 in which it is in snug and slightly stressed engagement with the under side of the piston I3. Thus the stirrup tends to lift the piston upwardly and to pull relatively downwardly on the yoke arms 38 with the result that the under surface of the pivot I4 is forced downwardly firmly in engagement with the complementary bearing surface of the piston l3 where the piston engages the pivot. Likewise the arms 43 of the stirrup yieldably urge and assist in maintaining the piston [3 in a centrally disposed position transversely, with its axis substantially intersecting the axis of the needle bar. As a result the downward force of the piston is exerted centrally on the needle bar so as not to tend to warp or drive it laterally of the plane of the axes of the bar and piston.

Referring next to the spring 31, as the lever I0 is rocked to move the end connected to the needle bar downwardly to drive the needle bar downwardly on the sewing stroke, the piston slides inwardly axially in its sleeve l2 so that the pivot l4 may move along a vertical path instead of along an arcuate path as does the end of the lever I3. Correspondingly, as the lever is rocked to lift the needle bar the piston slides outwardly axially of the sleeve T2. The spring 3! is tensioned so that during this movement of the piston I3 inwardly and outwardly it exerts inward pull to eliminate any slack. The stressing of thisspring, especially when the innermost end is secured at a point slightly above the axis of the piston, tends to lift the inner end of the yoke arms 38 upwardly thus drawing the crest 42 more firmly against the under side of the piston 3, thus yieldably holding the complementary bearing surfaces of the piston and pivot l4 firmly together and holding the piston firmly against the upper wall of the sleeve l2. Consequently, a firm stroke is delivered and the pounding which would otherwise occur were clearance permitted between these respective bearing surfaces, is eliminated. Due to the rapid rocking movement of the lever l0, there is a tendency for the piston to fly outwardly axially. This is overcome by the spring 31 which holds the piston inwardly yieldably allowing it to move axially only a sufficient amount so that'its outer end follows a vertical path. This in turn exerts an inward pull on the upper end of the needle bar tending to move it from its inwardly slanting position to an upright position, thus insuring a direct downward shove of the needle bar. As explained before the normal tendency of the bar is to slope inwardly toward the bottom and since this is overcome by the spring the needle bar will operate in a true vertical plane and since a firm steady downward shove is imparted to the needle while in this position and without sharp impact or vibration, the needle will penetrate much heavier material and sew effectively therethrough.

Another effect resulting from the spring 3? is that the wall 2| of the slot !5 is held in more effective operating position relative to the cam 18. Since the element is drawn inwardly by the spring loss or delay in its engagement with the cam 18 and premature disengagement are all eliminated. Consequently, a truer operation of the check lever at the proper instant results.

The conjoint action of these springs and the yoke arms also retains the piston [3 in its proper circumferential position in the sleeve i2 so there is no binding in the sleeve, on the pivot, against the upper end of the needle bar, or against the element [8. Lastly the spring 30 is stressed to draw the needle bar driving lever in the direction for driving the needle on the sewing stroke. This eliminates the play on the pin [4 and further assists in holding the piston l3 against the upper wall of the sleeve and against its pivot I4.

This assures a steady downward shove by the lever Ill and prevents the pounding on the pivots II or M or on the piston when the lever is moved on the withdrawal stroke. This same force tends to seat the lever ll! firmly on the pivot II or to seat the pivot l I firmly against its complementary bearing surfaces, in case the pivot H is such that it rocks with the lever Hi. This again eliminates play and resultant jamming and pounding of the elements.

Another result effected by the spring 30 is the retention of the driving lever 9 in snug yieldable engagement with the face of the cam 8 during part of the operating stroke. Furthermore, when the lever 9 engages and disengages the cams l and 8 during the respective portions of the revolutions of the disc 6, it is not kicked or slapped back and forth rapidly during the instant of changing but retains its position against one cam until actually forced into engagement with the other cam. Thus any play in the various elements described is substantially eliminated and slapping or undue vibration of the various parts of the sewing machine is eliminated and smooth operation effected. Since the vibration and pounding set up by these parts are transmitted both directly and indirectly to the internal mechanism of the machine, their elimination reduces the wear on the internal mechanism and renders the operation more smooth, even, and efiicient.

It has been demonstrated by actual operation of machines equipped with the device of the present invention that the machine, though made only for light patching work and work on uppers, will, when so equipped, penetrate and sew easily on much heavier materials and will penetrate and sew smoothly through the usual counters of shoes and even as much as two thicknesses of counter, an operation impossible on such. machines when not equipped with the device.

It is apparent from the above description that there is provided a very simple and effective device which may be readily installed in machines of this type and the principles of which may be found useful in other types of sewing machines for this purpose' Obviously, modifications may be made in the device without departing'from the concept of the present invention, the specific form shown being only for purposes of illustration.

Having thus described the invention, what is claimed is:

1. In a sewing machine of the type described having a rockable needle barldriving lever, a reciprocable needle bar, a piston, means pivotally connecting the outer end of the piston to the needle bar, and a sleeve on the end of the needle bar driving lever adjacent the needle bar telescopically mounting said piston for axial reciprocating movement, a member connected at one end to said pivot means, a spring connected to the other end of said member operable toexert an axial force on the piston for urging the piston toward a telescoped position, a second spring anchored at one end and operably connected by its other end to the needle bar driving lever intermediate the said end of said lever and the rocking axis thereof for urging the said end of said lever downwardly in the directior f movement for the sewing stroke.

2. The combination with a sewing machine of the shoe patching type having a substantially horizontal arm, a needle bar reciprocable vertically at one end of said arm, a needle bar driving lever extending longitudinally of said arm and adapted to rock thereon in a vertical plane parallel to the arm, means connecting one end of the needle bar driving lever to the needle bar for reciprocating the needle bar when the lever is rocked, and lever means at the other end of the arm engaging a driving cam for rocking said lever, of a tension spring connected at one end to said arm and at the other end to the needle bar driving lever between its rocking axis and its point of connection with the needle bar for holding the lever means and cam in yieldable contact during part of the driving stroke and for urging the needle bar driving lever in the direction for operating the needle bar on its sewing stroke.

3. In a sewing machine of the shoe patching type having a rockable needle bar driving lever, a reciprocable needle bar, a piston, a supporting guide on the needle bar driving lever mounting the piston for axial reciprocable movement, means pivotally connecting the outer end of the piston to the needle bar for reciprocating the bar consequent upon rocking of said lever, a member connected at the outer end to the pivot means, means yieldably connecting the inner end of the member to the needle bar driving lever, and a shoulder carried by said member and engaging the under surface of the piston and operable to exert upward pressure on the piston.

i. In a sewing machine of the shoe patching type having a rockable needle bar driving lever, a reciprocable needle bar, a sleeve on the driving lever, a piston mounted in said sleeve and reciprocable axially relative thereto, and pivotally connected at its outer end to the needle bar for reciprocating the needle bar consequent upon rocking of said needle bar driving lever, a yoke pivotally connected at its outer end to the outer end portion of the piston and extending toward the needle bar driving lever beyond the sleeve, the arms of said yoke being disposed on opposite sides of said piston and sleeve and spaced therefrom, a spring secured to the inner end of the yoke and to the said needle bar driving lever and operable to yieldably urge said yoke in a direction to retract the piston into said sleeve.

5. In a sewing machine of the shoe patching type having a rockable needle bar driving lever, a reciprocable needle bar, a sleeve on the needle bar driving lever, a piston mounted in said sleeve and reciprocable axially relative thereto, and a pivot means connecting the outer end of the piston to the needle bar for reciprocating the needle bar consequent upon rocking of said needle bar driving lever, a yoke connected at its outer end to the pivot means and extending toward the driving lever beyond the sleeve, the arms of said yoke being disposed on opposite sides of said piston and sleeve and spaced therefrom, a spring secured to the inner end of the yoke and to the said needle bar driving lever, said spring being operable to yieldably urge said yoke in a direction to retract the piston into said sleeve, and a stirrup carried by the yoke between the arms thereof and engaging the piston, said stirrup being operable to exert upward pressure on the piston consequent upon upward movement of the inner end of the yoke.

6. In a sewing machine of the shoe patching type having a rockable needle bar driving lever, a reciprocable needle bar, a sleeve on the driving lever, a piston mounted in said sleeve and reciprocable axially relative thereto, and a pivot means connecting the outer end of the piston to the needle bar for reciprocating the needle bar consequent upon rocking of said lever, a yoke connected at its outer end to the pivot means and extending toward the needle bar driving lever beyond the sleeve, the arms of said yoke being disposed on opposite sides of said piston and sleeve and spaced therefrom, a spring secured to the inner end of the yoke and to the said needle bar driving lever, said spring being operable to yieldably urge said yoke in a direction to retract the piston into said sleeve, a stirrup carried by the yoke between the arms and engaging the under side of the piston, an upwardly extending rest on the stirrup, and a recess on the under side of said piston engageable by said rest, said rest and recess walls being cooperable to maintain said piston in fixed circumferential and lateral position.

'7. In a sewing machine of the shoe patching type having a. rockable needle bar driving lever, a reciprocable needle bar, a sleeve on the driving lever, a piston mounted in said sleeve and. reciprocable axially relative thereto, and pivotally connected at its outer end to the needle bar for reciprocating the needle bar consequent upon rocking of said needle bar driving lever, a yoke pivotally connected at its outer end to the outer end portion of the piston and extending toward the needle bar driving lever beyond the sleeve, the arms of said yoke being disposed on opposite sides of said piston and sleeve and spaced therefrom, a spring secured to the inner end of the yoke and to the said needle bar driving lever and operable to yieldably urge said yoke in a direction to retract the piston into said sleeve.

8. In a sewing machine of the class described including the needle bar, a lever for operating the same, a pivot connecting the needle bar and lever, a bracket connected with the machine, and a spring connecting a part of the bracket with the pivot between the needle bar and the lever.

ANNA LUPSA PETERS, Administratrix of the Estate of Nicholas Peters,

' Deceased. 

